The present invention relates to a three conductor bundle damping spacer that is structurally strong yet extremely light in weight and economical to manufacture.
In FIGS. 3 and 4 of U.S. Pat. No. 3,617,609, issued on Nov. 2, 1971 in the name of Paul D. Tuttle, a frameless damping spacer is shown having a triangular configuration in side elevation (FIG. 3), the spacer being comprised of three rigid, elongated arms and three conductor clamps, with a pair of the arms connected together at each corner of the spacer. Each arm of the spacer is bifurcated at the end thereof remote from the conductor clamp to provide a yoke of two parallel arm portions, these parallel arm portions being disposed on both sides of a single arm portion of each arm at the location at which the arm portions are connected together. The single arm portion and the yoke arm portions are connected together by a rigid pin and a closed coil, damping spring extending through an opening provided in the single arm portion aligned with openings provided in the arms of the yoke portions. In addition, the yoke arm portions are spaced from the sides of the single arm portion by open coil springs surrounding the closed coil spring.
Structures similar to the damping spacer of the above Tuttle patent for spacing and damping two conductor bundles are shown in FIGS. 1 to 3 of the present inventor's (Hawkins) U.S. Pat. No. 3,870,815, issued on Mar. 11, 1975.
As shown in the Tuttle and Hawkins patents, the damping springs are exposed to the surrounding elements though, as depicted in FIG. 1 of the Hawkins patent, the damping springs can be enclosed by a cylinder or sleeve 36 employed to center the center arms of the spacer on the springs. In addition, the damping springs might be enclosed by additional means, such as elastomeric boots, though the use of such additional components would involve additional costs that would be reflected in the cost of the damping spacer. Similarly, the cost of the centering cylinders is reflected in the cost of the damping spacer.
Further, the Tuttle and Hawkins device, because of the yoke design employed in these devices, require rather long springs and spring retaining pins. As can be appreciated, a long pin or shaft will be susceptible to bending moments that a short pin will not encounter. Thus, the pins in the Tuttle and Hawkins spacers must be of substantial strength, such strength requiring costly pin structures resulting in a costly spacer device.
Another aspect of the Tuttle and Hawkins devices is the nature of the casting and manufacturing processes involved. It will be noted that the holes provided in each yoke portion of these devices extend in a direction perpendicular to the plane of the yoke. Such holes are therefore difficult to cast because it is impossible to remove the yoke and its clamp portion from a sand mold if metal extends in a direction (in such holes) normal to the direction the component is removed from the mold. Thus, to provide the spacer arms of the Tuttle and Hawkins devices with appropriate holes, the holes must be drilled, which drilling is reflected in the cost of the completed spacing device.